Down draft room



Sept. 29, 1931. I L. D. PEIK 1,825,542

DOWN DRAFT ROOM Filed May 13, 192 7 SheetsSheet 1 BY MMLZQM ATTORNEY Sept. 29, 1931. D. PEIK DOWN/DRAFT ROOM Filed May 13, 1927 7 Sheets-Sheet 2 lN VENTOR law/J D PEI/f BY 2% WM ATTORNEY Sept. 29, 1931'. L. D. PElK DOWN DRAFT ROOM Filed May 15. 1927 7 Sheets-Sheet 3 f r u C c r l O O O a o o o omok f o o o lNVENTOR 101/10 0. PE/ r ATTORNEY Sept, 29, 1931. L. D. PEIK 1,

- Down DRAFT ROOM Filed May 15, 19 27 7 Sheets-Sheet 5 IIIWWJ lllllll INV LOU/J- D PE! ATTQ Y BY MW'M Sept. 29, 1931. D, PEIK 1,825,542

DOWN DRAFT ROOM Filed May 13, 1927 7 Sheets-Sheet 6 INVENTOR 1001.1 D. PEI/f [Z ATTORNEY Patented Sept. 29, 1931 UNITED stares PATENT OFFICE LOUIS 13. PEIK, OF MISIIAWAKA, INDIANA, ASSIGNOR i EO THE AMERICAN FOUNDRY EQUIPMENT COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE DOWN DRAFT ROOM This invention relates to abrasive blasting apparatus, and more particularly, ,to means for separating and recovering used abrasive material andyreconditioning the samefor further use.

' In foundry practice it is often necessary to treat-rough castings for the removal of foreign substances, and for properly conditioning the surface thereof. One standard 0 method of accomplishing this is to direct i abrasive in the form of a fine stream or spray against the surface with suflicient velocity to forcibly remove undesiredmaterial. A substantially closed chamber or room is employed to prevent the dust caused by the blast of abraslvefrom spreading un necessarily and disturbing the operation of other parts of the plant. v

This invention relates more specifically to a method and means for separatingthe abrasivematerial from undesired substances and forv transferring the same from the blasting room to the reserve hopper. In accordance therewith a vibrating member,

.2 such as a transfer pan, is utilized to receive the abrasive material which has fallen through the floor of the blasting room, and after removing the dust and undesired large particles, such as tailings, to deposit the cleaned abrasive in a suitablehopper from which it may be readily removed to. the sand blast tank for use in further blasting operations. I

To effect the above mentioned transfer of abrasive material in accordance with this invention, a longitudinal vibratory movement may be imparted to the transfer pan for causing the materials thereinto gradually move :from one end thereof, where they are deposited after passing through the floor of the blasting room, to the other end of the pan-which is provided with a screen for allowing thefine particles to be discharged and. for causing the large particles or tailings to continue over the end of the pan, whence they are discharged into a suitable receptacle.

This invention also relates to a method of ventilation by means of which the dust and other light particles are removed from the abrasive material in a strong current of air, while any abrasive which is picked up and carried along therewith is returned to the transfer pan. A secondary zone of dust removalgmay also be included in the transfer pan directly over the screening area by providing suitable openings in the air discharge pipe.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be specifically pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization, may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which like reference characters have been used to denote like parts in the various figures. Since such illustration is", however, primarily for purposes of disclosure, it will be understood that the structure and the method of operation thereof mayibe modified in various respects without departing from the broad spirit and scope of the invention;

One embodiment of the invention has been shown' for purposes of illustration in the accompanying drawings, in which Fig- 1 is an elevation of a blasting apparatus constructed in accordance with this invention;

Fig. 2 is a plan view of ventilating duct;

Fig. 3 is aside elevation thereof; V Fig. 4is a plan'view of the transfer pan and screen;

Fig. 5 is a section of the transfer pan taken on .theline 55 of Fig. l;

Fig. 6 is a side elevation of the vibrating mechanism;

Fig. 7 is an end elevation thereof; Fig. 8 is an elevation, partly in section, of the blast tank and the hopper associated therewith;

the hopper and Fig. 9 is a plan view of the blast tank and hopper;

Figs. 10 and 11 are side and end elevations of a type of blasting apparatus in which the abrasive supply tank is located above the fioor level of the blasting room; and

Figs. 12 and 13 are side and end elevations of a type of blasting apparatus in which the abrasive supply tank is located above the floor level of the blasting room and the material is raised thereto by means of air pressure.

In the following description and in the claims the various parts of the apparatus and details of steps in the invention will be identified by specific names for convenience but they are intended to be as generic in their application as the art will permit.

Referring to the figures more in detail, Fig. 1 discloses a down draft room comprising imperforate side walls 15 and a louvred ceiling 16, through which a current of ventilating air may be drawn. A blasting table 17, which may be of the rotary type, is included at one side of the room for supporting'the articles being treated, and a blasting nozzle 18 is located in operative position with respect thereto whereby a suitable blast may be directed upon articles supported upon said table, and the used material may be drawn through perforated floor 19 and hopper 20* into transfer pan 21, which will be hereinafter described.

- The used material will be drawn through i perforated fioor 19 by the strong current of air which flows through the louvres in ceiling 16 andpasses through the floor and out through the discharge pipe 22 anddust separator 23. Suitable means, such as a fan, (not shown), may be employed for generating the required air pressure. Floor 19 may comprise a plurality of grates having comparatively large openings between the various elements thereof, supported upon a suitable framework, the details of which form no part of the present invention.

The ventilating system and air ducts are shown more in detail in Figs. 2 and 3', pipe extending a substantial distance beneath the floor of the down draft room, and being provided with an open end 24 and a perforated top portion A discharge opening 26 may be provided in pipe 22 adjacent the upturned portion thereof for permitting abrasive materials, which may have been carried with the current of air through said pipe, to be discharged into the transfer pan 21. Pipe 22 is provided with a dust separation means 23 in which the velocity of the air is decreased to such a value that the larger particles, such as portions of abrasive material, are allowed to separate therefrom and to fall by gravity through pipe 22 and openings 26 therein into the aforesaid transfer pan. Member 27 is provided beneath opening 26 to direct material falling therethrough into a suitable aligned opening in the top of the pan 21.

The transfer pan 21 is shown more in detail in Figs. 4 and 5, and comprises a section 30 having an imperforate bottom and a suitable top opening to receive the lower portion of hopper 20. The section of the bottom of transfer pan 21 over discharge hopper 31 is provided with a screen 32 of suitable mesh to permit the blasting material to pass therethrough while preventing the passage of larger undesired substances. The end of transfer pan- 21 adjacent screen 32 may be tapered so as to concentrate the tailings and todischarge the same into a suitable container 33' (Fig. 1).

In order to insure a comparatively tight fit between pan 21 and-hopper 20, a plurality of resilient members 34 may be secured around the sides of pan 22 for contacting with the outer surface of hopper 20 while permitting relative movement of the two elements as the transfer pan is vibrated. The pan 21 maybe mounted in any suitable manner to provide for longitudinal movement, such as by flexible links 35 (Fig. 1) and 36 (Fig. 6), said links being attached to the floor beams or other fixed portion of the apparatus.

A suitable means for vibrating pan 21 which may be employed if desired, is disclosed in Figs. 6 and 7, and comprises a cam member 40 which may be rotated by motor 41 through suitable power transmission connection, such as belt 42; A roller 43 iS rig-- idly secured to the framework of pan 21 and ispositioned for co-operation with cam 40. Spring 4.4 may be connected between a stationary portion of the apparatus and upstanding arm 45 of pan 21 for resiliently urging the transfer pan toward cam 40; Plunger 16 is shown as secured to the end of transfer pan 21 and contacts with a fixed member 47 for limiting'the movement of said pan.

Cam 40 in rotating forces roller 43" and the apparatus associated therewith against the tension of spring 44. When this force is relieved said spring operates to pull pan 21 back to its original positionuntil said pan is suddenly stopped by the impact of plunger 46 against member 47.

The abrasive supply tank 50 and hopper 31 are shown more in detail in Figs. 8' and 9. Hopper 31 is designed to co-operate with screen 32 in transfer pan 21 and to receive material passed therethrough. Abrasive supply tank 50 may be of any desired form for receiving and retainin a supply of abrasive material and feeding the same to a mixing chamber 51 wherein it is picked up by the air current and carried to nozzle 18 for further blasting operations.

In thetype of'tank shown for the purpose ofillustration, hopper 31 is made in sufficient capacity to retain a considerable portion of abrasive material which is discharged into tank 50,- when valve 52 is opened. A door 53 may be provided for inspection purposes if desired. 1 i v i In the operation of tlie'apparatus thus'far described, a casting or other material whose surface'is to be treated may be placed upon rotary table17 and the table revolved to bring the casting inside the downdraft room. An operator stationedtherein may then direct a blast of abrasive material upon the surface of the casting bymeans of flexible nozzle 18. The blasting may be regulated by suitable control means or valves which form'no part'of the present invention and consequently have not been described in detail. i

The used abrasivematerial falls through the perforated floor 19 and isdirected by means of hopper 20 onto transfer pan 21.

A strong current of air may be caused to circulate from the louvres in the top portion of the down draft room through the perforated floor and out through pipe 22 and the apparatus connected thereto. The vertical air current not only prevents dust from accumulating in the room and impairing the vision of the operator but also positively carries the fine used abrasive material through the perforated floor.

The air current is preferably maintained sufiiciently strong to pick up dust particles and other substances that are finer than the abrasive and to carry them out through pipe 22. Should the air current in so doing also carry along small amounts of abrasive material, the latter will be released as the veloc ity of the air current decreases in pipe 22 and in chamber 28. The particles of the abrasive material then fall through openings 26 in pipe 22 and are directed by hopper 27 onto screen 32 of-the transfer pan.

A secondary current of air is also produced through hopper 20 and transfer pan 21 up through openings 26 to pipe 22. This current of air serves to pick up any remaining dust particles which may be pres ent and effectively cleanse the abrasive material.

After the materials have been deposited upon transfer pan 21 theyare caused to be gradually moved, due to the vibrations of said pan, from the initial position under hopper 20 to a position over screen 32 whence they are deposited in hopper 31 and stored for subsequent introduction into the J. tank 50. The particles which are not passed through screen 32 are removed to the eX- treme end of the transfer pan and deposited in receptacle 33.

When the required amount of material has been received in hopper 31 valve 52 may 65 be opened and the material introduced into tank 50 whence it may be fed to mixing chamber 51 and picked up by a current of compressedair and conducted to nozzle 18 for further blasting operations.

A type of apparatus has been in Figs. 10 and 11 which employs the same downdraft room, hopper and transfer pan as that described above but is adapted to be utilized where there is not sufiicient space beneath the down draft room for the abrasive supply tank. In' accordance with Figs. 10 and 11 therefore, the materialwhich is deposited from the transfer pan into hopper 31 is picked up by a series of travelling buckets G and elevated'to a position where it may fall through chute 61 into hopper 62 whence it may be deposited into abrasive supply tank 50 as aforementioned. The Various details of the apparatus employed are similarto those described in connection with Figs. 1 to 9 with the exception of the bucket conveyor for elevating the material before depositing it into'hopper of the abrasive supply tank, consequently they have not been shown or described in Figs. and

In the modification shown inFigs. 12 and 13, the various parts which have been heretofore described are given the same reference numerals, and consequently will not, be again described in detail. In these figures, however, the abrasive supply tank is located above the floor level of the down draft room 15. The used abrasive which is passed through the floor of the down draft room and has been transferred by transfer pan 21 into hopper 31, iswpicked up by a light current of air which is applied to pipe from blower 71, and is carried through said pipe 70 into a dust separationchamber 72, whence it is deposited in the hopper of the abrasive supply tank 50. The mixture strikes against aplurality of bafile plates 73 contained in the. dustseparation chamber- 72, and by reason of the deflection and change in velocity, the abrasive material is dropped from the air stream, whilethe dust which may be present, is allowed to remain with the air and escape through pipe 74. r

The operation of the system shown in Figs. 12 and 13 is similar to that shown in Figs. 10 and 11, inasmuch as the abrasive material is removed from the transfer pan and forcibly raised to an elevated hopper. This is accomplished in the apparatus disclosed in the latter figures, however, by means of an air blast, whereas Figs. 10 and 11 disclose a traveling elevator. Obviously, any other suitable method could be used, if desired. 2

By constructing apparatus in accordance with this invention, the abrasive material may be removed from the down draft room, fine particles such as dust removed therefrom, large particles or tailingsseparated disclosed and the material may then be deposited into the supply hopper ready for further use,

all of. the above features taking place in a Single operation. By imparting a creep- 5 ing motion to the material in transfer pan 21,.the removal of both coarse and large particles is facilitated and the abrasive material is caused to positively travel over the screen 32 before the material can reach the rece )taclc 83. Furthermore, the secondary draft passing through openings 26 serves to further remove dust particles and insure a complete cleansing of the abrasive material.

Vhile certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

Vhat is claimed is 1. A blasting apparatus comprising a blasting chamber having a perforated floor, a down draft for assisting spent abrasive material therethrough, a transfer pan beneath said chamber having material receiving and material discharging sections, an exhaust duct whereby said air current may be used to pick up dust particles and separate the same from the abrasive material, and a secondary opening in said duct substantially over said material discharging portion, means for causing said air current to pass over said pan and through said secondary opening whereby further quantities of dust may be removed.

2. A blasting chamber having a perforated floor and a louvred ceiling, an abrasive transfer member beneath said chamber, a hopper for receiving material and directing the same to said transfer member, an exhaust duct associated with said hopper and having an. upwardly extending section of increased cross section whereby the air velocity therein may be decreased and abrasive material allowed to separate therefrom, and an opening in said duct through which said separated abrasive material may fall onto said transfer member.

3. A blasting chamber having a perforated floor and a louvred ceiling, an abrasive transfer member beneath said chamber, a hopper for receiving material and directing the same to said transfer member, an exhaust duct associated with said hopper and having an upwardly extending section of increased cross section whereby the air ve locity therein may be decreased and abrasive material allowed to separate therefrom, an opening in said duct, and means for producing an air current through said opening for the removal of dust from ab 'asive material in said transfer member.

4. A blasting chamber having a perforated floor and a louvred ceiling, an abrasive transfer member beneath said chamber, a hopper for receiving material and directing same to said transfer member, an exhaust duct associated with said hopper and having an upwardly extending section of increased cross section whereby the air velocity therein may be decreased and the abrasive material allowed to separate therefrom, and an opening in said ductthrough which said separated abrasive material may fall onto said transfer member, and through which a secondary air current may be created over said transfer member and up through said opening, whereby. dust may be picked up and removed.

In testimony whereof I have hereunto set my hand.

LOUIS D. PEIK. 

